Systems and methods are disclosed for navigating a surgical device toward a target organ in the body of a patient. An example method includes providing a surgical needle and a guide wire, the surgical needle configured for insertion into a vein or a beating heart. The method also includes holding the guide wire within the surgical needle while the surgical needle is inserted into the vein or the beating heart. The method also includes generating output in two modes, the output based on at least one medical positioning system (MPS) sensor on the guide wire, the output corresponding to a position of the surgical needle and the guide wire for navigating the surgical needle and the guide wire toward a target in the vein or the heart. The methods can be carried out directly by a physician or via a computer processor-based surgical system.